title: Synapsin I is structurally similar to ATP-utilizing enzymes.
abstract: Synapsins are abundant synaptic vesicle proteins with an essential regulatory function in the nerve terminal. We determined the crystal structure of a fragment (synC) consisting of residues 110-420 of bovine synapsin I; synC coincides with the large middle domain (C-domain), the most conserved domain of synapsins. SynC molecules are folded into compact domains and form closely associated dimers. SynC monomers are strikingly similar in structure to a family of ATP-utilizing enzymes, which includes glutathione synthetase and D-alanine:D-alanine ligase. SynC binds ATP in a Ca2+-dependent manner. The crystal structure of synC in complex with ATPgammaS and Ca2+ explains the preference of synC for Ca2+ over Mg2+. Our results suggest that synapsins may also be ATP-utilizing enzymes.
authors.affiliation: Howard Hughes Medical Institute, Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas 75235-9050, USA.
authors.forename: L
authors.initials: L
authors.lastname: Esser
authors.forename: C R
authors.initials: CR
authors.lastname: Wang
authors.forename: M
authors.initials: M
authors.lastname: Hosaka
authors.forename: C S
authors.initials: CS
authors.lastname: Smagula
authors.forename: T C
authors.initials: TC
authors.lastname: Südhof
authors.forename: J
authors.initials: J
authors.lastname: Deisenhofer
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D002417:Cattle; D018360:Crystallography, X-Ray; D019281:Dimerization; D005981:Glutathione Synthase / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D010453:Peptide Synthases / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship; D016704:Synapsins / Q000737:chemistry* / Q000378:metabolism
chemical_list: D016704:Synapsins; D000255:Adenosine Triphosphate; D010453:Peptide Synthases; D005981:Glutathione Synthase; C019638:D-alanylalanine synthetase; D002118:Calcium